Project Summary/Abstract: Biomedical Core B-Mouse Metabolism and Imaging The study of obesity, nutrition, and metabolism relies on methods to measure feeding patterns, metabolic rate, activity, body content, and fat distribution in humans (Core A: Human Metabolism) and model organisms (Core B: Mouse Metabolism and Imaging Core). The study of these parameters within model organisms enables the researcher to rigorously control both the test subjects' genetics (Core C: Genetics) and environments (Core B) to better test hypotheses about the factors that control energy homeostasis. 21 of the 44 investigators in the proposed UCSF-NORC currently conduct research studies in which these types of parameters must be monitored in rodent models; another 6 NORC investigators indicate that their research has developed to a point where their use of facilities in the Mouse Metabolism and Imaging Core is imminent. These studies are conducted primarily in two facilities operated by different departments. The UCSF-NORC will coordinate and focus those facilities towards the provision of exceptional quality research services in technologically challenging areas of high need to the NORC membership. Experts within the Core will be able to keep abreast of the rapidly evolving application of these sophisticated methods and ensure that NORC researchers are trained in their proper implementation. The presence of the facilities, and the availability of NORC support that is designed to assist the entry of NORC researchers into technologically unfamiliar areas, will ensure the success of UCSF-NORC research. The NORC Mouse Metabolism and Imaging Core will provide access to, assistance with and training in the use of sophisticated methods and instruments for those studies. The Core will provide tools and facilities for: 1. Precisely measuring feeding, basal metabolism, motor activities, and thermoregulation in mice. 2. Analyzing lean mass, fat mass, free body fluids, and total body water in intact mice. 3. Visualizing and quantitatively measuring anatomical structures relevant to obesity, nutrition and metabolism with highly advanced radiologic imaging. 4. Imaging the fat and water content, or other functional measurement involving radiologic tracers, within those anatomical structures. Core B facilities will enable non-invasive methods that permit mice to be followed over time. The ability to conduct longitudinal studies is particularly significant for tracking the changes in body composition, feeding behavior, and metabolic activity during the development of obesity and its associated complications. Overall, this Core will lower methodologic barriers to help NORC researchers achieve the efficient and proper application of a series of highly sophisticated tools. These capabilities will accelerate a variety of diverse and interrelated studies in of obesity, nutrition, food intake, and metabolism.